Just did a quick search using "Pininfarina" & "Plymouth", and although this same photograph shows up numerous times, none of them have a date. The Ghia Plymouth XX-500, which supposedly was the car that the puzzle car was in design competition with, shows up on different web sites dated as either a 1950 or 1951. As these cars took a while to build, even by the speedy Italians, I would say a year or two either side of 1950.